A method for creating a triggering decision for restraint means is known from European Patent No. EP 0 458 796. In the case of the triggering algorithm described in this document, the triggering threshold curve depends on the measured acceleration. Triggering situations can be distinguished from non-triggering situations by suitable selection of the triggering threshold. Specifically, the triggering of restraint means (e.g. airbags, belt tensioners) is to be prevented when the vehicle experiences only a minor crash or, for example, drives over railroad tracks or curbs, in which context the vehicle occupants are not exposed to any risk of injury. In severe crashes that in any case present a risk of injury to the vehicle occupants, on the other hand, triggering of the restraint means is to be absolutely guaranteed. Since there is a very fine distinction between crashes that require triggering of the restraint means and crashes in which no triggering should occur, it may certainly happen that an incorrect decision is made regarding triggering or non-triggering of the restraint means. In order to achieve a faster and more robust triggering decision in vehicle crashes, it is described in German Patent No. DE 44 45 996, as stated initially, that the triggering threshold curve and thus the triggering sensitivity be selected as a function of an ascertained crash severity. For that purpose, a frequency analysis of the measured acceleration is performed here, and the dominant components in the spectrum of the acceleration signal are selected and appropriately evaluated. The integration of the acceleration signal is influenced as a function of this frequency analysis of the acceleration signal, in that the acceleration to be integrated is more heavily weighted in critical situations, so that a triggering threshold is exceeded more quickly.
It is an object of the present invention to provide a method of the kind cited initially with which, by comparison with the existing art, an even more reliable and robust triggering decision for restraint means can be made.